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DateTime Format check

Quick Question
Value passed in ActivationDate or ExpirationDate string, must be in either of the two formats stated below:Format 1:YYYY-MM-DD & Format 2: YYYY-MM-DD HH:MM
If the date values are not in either of the above format, then it should report back appropriate error message.
Any clue? Thanks in advance

You can use DateTime.TryParseExact, using a string[] with the valid formats:
string[] formats = new string[] { "yyyy-MM-dd", "yyyy-MM-dd HH:mm" };
string s = "2017-12-01 12:23";
DateTime date;
bool converted = DateTime.TryParseExact(s, formats, CultureInfo.InvariantCulture, DateTimeStyles.None, out date);
With this code, you get in convertedif the input date was in a valid format, and in date the parsed DateTime

You can use ParseExact() with try-catch:
string date = "2017-02-01";
DateTime dt = default(DateTime);
try
{
dt = DateTime.ParseExact(date, new string[] {"yyyy-MM-dd", "yyyy-MM-dd hh:mm"}, CultureInfo.InvariantCulture, DateTimeStyles.None);
}
catch (FormatException ex)
{
//error
}
OR
Use TryParseExact():
string date = "2017-02-01";
DateTime dt;
if (DateTime.TryParseExact(date, new string[] {"yyyy-MM-dd", "yyyy-MM-DD hh:mm"}, CultureInfo.InvariantCulture, DateTimeStyles.None, out dt))
{
//do something and use "dt" variable
}
else
{
//error
}

How to get a datetime value within a string?

I've got a string that contains a value of datetime:
string myStr = "= '2015-12-01 00:00:00.000'";
How can I check if myStr contains a datetime value?
How can I get only the datetime value from myStr? The datetime value got from myStr should be: "2015-12-01 00:00:00.000".
The sample code that I have tried to do the task:
string myStr = "= '2015-12-01 00:00:00.000'";
Regex rgx = new Regex(#"\d{2}-\d{2}-\d{4}");
Match mat = rgx.Match(myStr);
if (mat.ToString() != "") //This will check if string contains datetime value
{
DateTime myDateTime = DateTime.Parse(mat.ToString()); //This will get the datetime value from string
}
Note: The result from the sample code above is: It can't check if myStr contains a datetime value. It can't get the datetime value from myStr.
You could help me to check if a string contains a datetime value, and get the datetime value within a string.

Try this
var myStr = "= '2015-12-01 00:00:00.000'";
var match = Regex.Matches(myStr, #"'(.*?)'")[0].Groups[1].Value;
DateTime result;
if (DateTime.TryParse(match.ToString(), out result)) {
// Your string has a valid DateTime and it is parsed in result
}
else {
// Invalid
}

There are two things we need to do:
Write a regex which get things that look like they might be a date. However, since dates can be exceedingly complex, we want to delegate that validation to the built-in DateTime library.
For each possible match, we want to validate that it's actually a date.
private IEnumerable<DateTime> GetDates(string str)
{
var dateSearcherRegex = new Regex(#"\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}.\d{3}");
foreach (Match match in dateSearcherRegex.Matches(str))
{
var matchedString = match.Groups[0].Value;
DateTime date;
if (DateTime.TryParseExact(matchedString, "yyyy-MM-dd hh:mm:ss.fff", CultureInfo.InvariantCulture, DateTimeStyles.None, out date))
{
yield return date;
}
}
}
And using it like this:
string myStr = "= '2015-12-01 00:00:00.000'";
var dates = GetDates(myStr);

string myStr = "= '2015-12-01 00:00:00.000'";
DateTime dt;
bool b = DateTime.TryParse(myStr.Split(' ')[1].Replace("'",string.Empty),out dt);
if (b)
{
Console.WriteLine("contains datetime");
}
else
{
Console.WriteLine("doesn't contain datetime");
}
Use TryParse function to check for DateTime values

If you still want using regex to parse the date:
Regex rgx = new Regex(#"\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}.\d{3}");
Match result = rgx.Match(myStr);
if (mat.Success)
{
DateTime myDateTime = DateTime.ParseExact(m.Value, "yyyy-MM-dd hh:mm:ss.fff", CultureInfo.InvariantCulture);
}
CMIIW.

Retrieve DateTime objects from a certain string

I have the following string:
"23/09/2015 08:00\r\n עד\r\n24/09/2015 08:00"
As you can see, we have two dates. One before the first \r\n and the other one after the second \r\n.
How can I retrieve DateTime objects from this string in C#? The only way I know is to use Substring but that retrieves the text after the first \r\n.

This may help
var stringValue = "23/09/2015 08:00\r\n עד\r\n24/09/2015 08:00";
var splitted = stringValue.Split(new string[]{"\r\n"},StringSplitOptions.RemoveEmptyEntries);
var firstStringDate = splitted[0];
var secondStringDate = splitted[2];
And to get the DateTime:
var firstDate = DateTime.ParseExact(splitted[0], "dd/MM/yyyy HH:mm", DateTimeFormatInfo.InvariantInfo);
var secondDate = DateTime.ParseExact(splitted[2], "dd/MM/yyyy HH:mm", DateTimeFormatInfo.InvariantInfo);

Split and TryParse the strings:
static IEnumerable<DateTime> extractDates(string inputString)
{
foreach (var item in inputString.Split(new string[] {"\r\n"}, StringSplitOptions.RemoveEmptyEntries))
{
DateTime dt;
if(DateTime.TryParseExact(item,
"dd/MM/yyyy HH:mm",
System.Globalization.CultureInfo.InvariantCulture,
System.Globalization.DateTimeStyles.None,
out dt))
yield return dt;
}
}

I would use myString.Split("\r\n") like so:
string[] dates = myString.Split("\r\n");
foreach (var dateString in dates)
{
DateTime dateTime;
if (DateTime.TryParse(dateString, out dateTime))
{
//Use dateTime here
}
}

Date format from Dutch to English

I have a date in string format (i.e in Dutch language), like "7 juli 2013". I want to convert it in English format. "Convert.toDateTime(strValue) throw exception as that converts only English format. I also try this
string strValue = "7 juli 2013";
CultureInfo ci = new CultureInfo("en-US");
strValue = strValue.ToString(ci);
but this is not working. What is the way to convert it?

string strValue = "7 juli 2013";
// Convert to DateTime
CultureInfo dutch = new CultureInfo("nl-NL", false);
DateTime dt = DateTime.Parse(strValue, dutch);
// Convert the DateTime to a string
CultureInfo ci = new CultureInfo("en-US", false);
strValue = dt.ToString("d MMM yyyy", ci);
You first convert the string to a DateTime, then .ToString the DateTime!
And, in general, it's false that Convert.ToDateTime uses only English. The overload you used uses the current culture of your pc (so on my pc it uses italian), and there is the Convert.ToDateTime(string, IFormatProvider) overload that accepts a CultureInfo.
Multilanguage... But note that this is wrong! You can't be sure that a word doesn't have different meaning in different places!!!
// The languages you want to recognize
var languages = new[] { "nl-NL", "it-IT" };
DateTime dt = DateTime.MinValue;
bool success = false;
foreach (var lang in languages)
{
if (DateTime.TryParse(strValue, new CultureInfo(lang, false), DateTimeStyles.AssumeLocal, out dt))
{
success = true;
break;
}
}
if (success)
{
CultureInfo ci = new CultureInfo("en-US", false);
strValue = dt.ToString("d MMM yyyy", ci);
}

String was not recognized as a valid DateTime

This is my first post here. The application is a winform I have set the culture for the application as en-GB but while checking and saving I convert it back to en-US I get this the error String was not recornized as a valid DateTime
CultureInfo currentCulture = new CultureInfo("en-US");
string strCheckDate = CheckConvertCulture(input);
string date = DateTime.Now.ToString("M/d/yyyy");
if (DateTime.ParseExact(strCheckDate,currentCulture.ToString(),null)> DateTime.ParseExact(date,currentCulture.ToString(),null))
{
return false;
}
else
{
return true;
}
What am I doing wrong here
This is my converCurrentCulture code
string strdate = string.Empty;
CultureInfo currentCulture = CultureInfo.CurrentCulture;
System.Globalization.DateTimeFormatInfo usDtfi = new System.Globalization.CultureInfo("en-US", false).DateTimeFormat;
if (currentCulture.ToString() != "en-US")
{
strdate = Convert.ToDateTime(Culturedate).ToString(usDtfi.ShortDatePattern);
}
else
{
strdate = Culturedate;
}
return strdate;
This is what I did to get it to work, but if a user selects an invalid date like 29/02/2013 will it work not sure,
CultureInfo currentCulture = new CultureInfo("en-GB");
string date = DateTime.Now.ToString("dd/MM/yyyy", currentCulture);
Since the application is default to en-GB
if (DateTime.Parse(input) > DateTime.Parse(date))
{
return false;
}
else
{
return true;
}

If this is actually your code:
CultureInfo currentCulture = new CultureInfo("en-US");
string strCheckDate = CheckConvertCulture(input);
if (DateTime.ParseExact(strCheckDate,currentCulture.ToString(),null)
then the problem is in your ParseExact, which translates to
if (DateTime.ParseExact(strCheckDate, "en-US", null))
You would be better off specifying the date in a specific format, and parsing that:
string format = "MM/dd/yyyy HH:mm:ss";
string strCheckDate = input.ToString(format);
// See note below about "why are you doing this?
if (DateTime.ParseExact(strCheckDate, format))
My big question is - why are you doing this? If you have two dates, why are you converting them both to strings, and then converting them back to dates to compare them?
return (input > date);
Please see the MSDN documentation for the proper use of DateTime.ParseExact.